Most of them just join in order to create a member profile and add spammy links to the profile signature (but then never post).

Pointless really as the member profiles on this forum are hidden from the public so can't be seen by the search engines. And that must be the only reason they create them as the links in them have no connection with the forum topics at all, so not at all likely to interest other members, who probably don't look at profiles of non posting members anyway.

May be automated bots. But I rather suspect the latest ones may be cheap human labour, probably using automated form filling tools - as the recent ones have managed to get through all the anti-bot tests. If that's what it is then not much I can do about it, and none of the anti-bot or anti-spam tests will work, and don't want to have to spend half an hour or so every day deleting the profiles.

Sorry.

Will approve you as soon as I can, usually within a day or two but sometimes may be off-line for several days.

May need to disable again, as I've been getting some obviously spam members from various unlikely places - a stream of users saying they are from Cambodia or Ukraine or whatever - and none at all from the places my main visitors come from such as US. One of them has just posted a spam post today.

However, I've updated the forum software, and made a minor change in verification, may be enough to fix it, will see.